At times during the life of a well a lateral is necessary to tap into an existing producing zone in a new location or to access a different producing zone, for example. This lateral is created by locating a diverter or whipstock a desired depth and orientation. In one trip operations, the whipstock has a series of mills attached to a lug at the top of a whipstock ramp. The milling assembly can have an initial mill, known as a window mill and one or more oblong mills generally shaped like a ripe watermelon and commonly referred to as watermelon mills. The window mill is initially diverted laterally by the ramp on the whipstock so as to begin the long window that is typically narrower near the top and gets wider further down as the window mill makes an exit and the first of what could be several watermelon mills enters the window started by the window mill. The ramp can be long enough to have the window and watermelon mills on or even extending beyond the whipstock ramp and through the window. Experience and modeling studies have shown that the weak link in this system is the threaded connection just above the uppermost watermelon mill. In the past, stresses on this joint have caused it to fail.
The present invention addresses this concern by strategically locating a protrusion on the exterior of the tubular between the upset area of the threaded connection and the topmost watermelon mill. As a result of doing this stress is concentrated at the reduced diameter below the protrusion and the degree of bending at the threaded connection is reduced. The reliability and service life of the threaded connection is increased. Those skilled in the art will more readily appreciate the scope of the invention from a review of the description of the preferred embodiment and associated drawings that appear below while recognizing that the full scope of the invention is to be found in the claims.